From patchwork Thu Sep 15 19:32:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Berger X-Patchwork-Id: 12977738 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFACAC32771 for ; Thu, 15 Sep 2022 19:33:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229803AbiIOTdU (ORCPT ); Thu, 15 Sep 2022 15:33:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229673AbiIOTdJ (ORCPT ); Thu, 15 Sep 2022 15:33:09 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C5819D13B; Thu, 15 Sep 2022 12:33:08 -0700 (PDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28FIVlDM010758; Thu, 15 Sep 2022 19:32:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=40feqhaBpdbLg8DyX1lE795k57r1AtKfKEdCt3hVgww=; b=ZZW3cnVSjTjejNzjk9r6JvA+ROXNGQ5XnE3bQSCdH4WQzp6jC+V85+lijNt9bPW9SfF9 Lm+EuK/q3LXEPLMocAILmFf74Z2bY90fEDP3Z3H6Ei5jnU4NTnLbth7NwYKcmymgU3Je V9ZlsyjGwpAU8IUmjnj1n/wIkVWZ26fiWxZIWVeVQjToQ1JJVfjDZciCH5J0QRFLd2ZC O3ZQMLw1/Ly7wT5g2yRln9Mp4d0g3ZeY9UrzTkW5orvk8R0Q4zXP6MpeUyvfYxSwaaXF 8hz3p38O8BA0Rl4OGds7KE33kNf90Diye0w00mJRPF5WShE4jzFtll+w5Yxu9gEYCijs cA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3jm9dkhrmr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Sep 2022 19:32:40 +0000 Received: from m0098399.ppops.net (m0098399.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 28FJWGsd006498; Thu, 15 Sep 2022 19:32:39 GMT Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3jm9dkhrm2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Sep 2022 19:32:39 +0000 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 28FJKmjC023949; Thu, 15 Sep 2022 19:32:38 GMT Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by ppma02dal.us.ibm.com with ESMTP id 3jm9170gt4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Sep 2022 19:32:38 +0000 Received: from b01ledav005.gho.pok.ibm.com (b01ledav005.gho.pok.ibm.com [9.57.199.110]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 28FJWb9w17498770 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 15 Sep 2022 19:32:37 GMT Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 21C70AE05C; Thu, 15 Sep 2022 19:32:37 +0000 (GMT) Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 02E2EAE062; Thu, 15 Sep 2022 19:32:37 +0000 (GMT) Received: from sbct-3.pok.ibm.com (unknown [9.47.158.153]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 15 Sep 2022 19:32:36 +0000 (GMT) From: Stefan Berger To: linux-integrity@vger.kernel.org Cc: zohar@linux.ibm.com, serge@hallyn.com, brauner@kernel.org, containers@lists.linux.dev, dmitry.kasatkin@gmail.com, ebiederm@xmission.com, krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com, mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com, puiterwi@redhat.com, jejb@linux.ibm.com, jamjoom@us.ibm.com, linux-kernel@vger.kernel.org, paul@paul-moore.com, rgb@redhat.com, linux-security-module@vger.kernel.org, jmorris@namei.org, jpenumak@redhat.com, Stefan Berger Subject: [PATCH v14 14/26] ima: Implement hierarchical processing of file accesses Date: Thu, 15 Sep 2022 15:32:09 -0400 Message-Id: <20220915193221.1728029-15-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220915193221.1728029-1-stefanb@linux.ibm.com> References: <20220915193221.1728029-1-stefanb@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: giAuV6mW7Wz5YlFhklp-piBeoTmYehEj X-Proofpoint-ORIG-GUID: 8-wUvvk-X-YVnVEclKf_MMIq39SrBJA8 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-15_10,2022-09-14_04,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 phishscore=0 suspectscore=0 spamscore=0 malwarescore=0 priorityscore=1501 bulkscore=0 clxscore=1015 impostorscore=0 adultscore=0 mlxscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2209150119 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Implement hierarchical processing of file accesses in IMA namespaces by walking the list of user namespaces towards the root. This way file accesses can be audited in an IMA namespace and also be evaluated against the IMA policies of parent IMA namespaces. Pass the user_namespace into process_measurement since we will be walking the hierarchy of user_namespaces towards the init_user_ns and we can easily derive the ima_namespace from the user_namespace. __process_measurement() returns either 0 or -EACCES. For hierarchical processing remember the -EACCES returned by this function but continue to the parent user namespace. At the end either return 0 or -EACCES if an error occurred in one of the IMA namespaces. Currently the ima_ns pointer of the user_namespace is always NULL except at the init_user_ns, so test ima_ns for NULL pointer and skip the call to __process_measurement() if it is NULL. Once IMA namespacing is fully enabled, the pointer may still be NULL due to late initialization of the IMA namespace. Signed-off-by: Stefan Berger Reviewed-by: Mimi Zohar Reviewed-by: Serge Hallyn --- v10: - Fixed compilation issue v9: - Switch callers to pass user_namespace rather than ima_namespace with potential NULL pointer - Add default case to switch statement and warn if this happens - Implement ima_ns_from_user_ns() in this patch now --- security/integrity/ima/ima.h | 8 ++++ security/integrity/ima/ima_main.c | 76 +++++++++++++++++++++++-------- 2 files changed, 65 insertions(+), 19 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 28a9842c566f..e662641772fd 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -497,4 +497,12 @@ struct user_namespace *ima_user_ns_from_file(const struct file *filp) return file_sb_user_ns(filp); } +static inline struct ima_namespace +*ima_ns_from_user_ns(struct user_namespace *user_ns) +{ + if (user_ns == &init_user_ns) + return &init_ima_ns; + return NULL; +} + #endif /* __LINUX_IMA_H */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 789415f65204..d2157c26d151 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -196,10 +196,10 @@ void ima_file_free(struct file *file) ima_check_last_writer(iint, inode, file); } -static int process_measurement(struct ima_namespace *ns, - struct file *file, const struct cred *cred, - u32 secid, char *buf, loff_t size, int mask, - enum ima_hooks func) +static int __process_measurement(struct ima_namespace *ns, + struct file *file, const struct cred *cred, + u32 secid, char *buf, loff_t size, int mask, + enum ima_hooks func) { struct inode *inode = file_inode(file); struct integrity_iint_cache *iint = NULL; @@ -391,6 +391,41 @@ static int process_measurement(struct ima_namespace *ns, return 0; } +static int process_measurement(struct user_namespace *user_ns, + struct file *file, const struct cred *cred, + u32 secid, char *buf, loff_t size, int mask, + enum ima_hooks func) +{ + struct ima_namespace *ns; + int ret = 0; + + while (user_ns) { + ns = ima_ns_from_user_ns(user_ns); + if (ns) { + int rc; + + rc = __process_measurement(ns, file, cred, secid, buf, + size, mask, func); + switch (rc) { + case 0: + break; + case -EACCES: + /* return this error at the end but continue */ + ret = -EACCES; + break; + default: + /* should not happen */ + ret = -EACCES; + WARN_ON_ONCE(true); + } + } + + user_ns = user_ns->parent; + } + + return ret; +} + /** * ima_file_mmap - based on policy, collect/store measurement. * @file: pointer to the file to be measured (May be NULL) @@ -404,13 +439,14 @@ static int process_measurement(struct ima_namespace *ns, */ int ima_file_mmap(struct file *file, unsigned long prot) { - struct ima_namespace *ns = &init_ima_ns; + struct user_namespace *user_ns = current_user_ns(); u32 secid; if (file && (prot & PROT_EXEC)) { security_current_getsecid_subj(&secid); - return process_measurement(ns, file, current_cred(), secid, - NULL, 0, MAY_EXEC, MMAP_CHECK); + return process_measurement(user_ns, file, current_cred(), + secid, NULL, 0, MAY_EXEC, + MMAP_CHECK); } return 0; @@ -486,19 +522,19 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot) */ int ima_bprm_check(struct linux_binprm *bprm) { - struct ima_namespace *ns = &init_ima_ns; + struct user_namespace *user_ns = current_user_ns(); int ret; u32 secid; security_current_getsecid_subj(&secid); - ret = process_measurement(ns, bprm->file, current_cred(), secid, NULL, - 0, MAY_EXEC, BPRM_CHECK); + ret = process_measurement(user_ns, bprm->file, current_cred(), secid, + NULL, 0, MAY_EXEC, BPRM_CHECK); if (ret) return ret; security_cred_getsecid(bprm->cred, &secid); - return process_measurement(ns, bprm->file, bprm->cred, secid, NULL, 0, - MAY_EXEC, CREDS_CHECK); + return process_measurement(user_ns, bprm->file, bprm->cred, secid, + NULL, 0, MAY_EXEC, CREDS_CHECK); } /** @@ -513,11 +549,12 @@ int ima_bprm_check(struct linux_binprm *bprm) */ int ima_file_check(struct file *file, int mask) { - struct ima_namespace *ns = &init_ima_ns; + struct user_namespace *user_ns = current_user_ns(); u32 secid; security_current_getsecid_subj(&secid); - return process_measurement(ns, file, current_cred(), secid, NULL, 0, + return process_measurement(user_ns, file, current_cred(), secid, + NULL, 0, mask & (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND), FILE_CHECK); } @@ -718,7 +755,7 @@ void ima_post_path_mknod(struct user_namespace *mnt_userns, int ima_read_file(struct file *file, enum kernel_read_file_id read_id, bool contents) { - struct ima_namespace *ns = &init_ima_ns; + struct user_namespace *user_ns = current_user_ns(); enum ima_hooks func; u32 secid; @@ -741,7 +778,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id, /* Read entire file for all partial reads. */ func = read_idmap[read_id] ?: FILE_CHECK; security_current_getsecid_subj(&secid); - return process_measurement(ns, file, current_cred(), secid, NULL, + return process_measurement(user_ns, file, current_cred(), secid, NULL, 0, MAY_READ, func); } @@ -769,7 +806,8 @@ const int read_idmap[READING_MAX_ID] = { int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id read_id) { - struct ima_namespace *ns = &init_ima_ns; + struct user_namespace *user_ns = current_user_ns(); + struct ima_namespace *ns = ima_ns_from_user_ns(user_ns); enum ima_hooks func; u32 secid; @@ -786,8 +824,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, func = read_idmap[read_id] ?: FILE_CHECK; security_current_getsecid_subj(&secid); - return process_measurement(ns, file, current_cred(), secid, buf, size, - MAY_READ, func); + return process_measurement(user_ns, file, current_cred(), secid, + buf, size, MAY_READ, func); } /**